Zanata spa

New endpoint for zanata-spa
- /locales 
    - list of locales enabled in zanata
- /projects/p/{projectSlug}/iterations/i/{versionSlug}/locales 
    - locales enabled in version
- /projects/p/{projectSlug}/iterations/i/{versionSlug}/r/{docId}/states/{localeId} 
    - list of {id, resId, states}
- /stats/proj/{projectSlug}/iter/{versionSlug}/doc/{encodedDocId*}/locale/{localeId} 
    - statistic
- /user
    - get user's information for the current authenticated user, equivalent to /user/{username} with the current user's username.
- /user/{username}

source and translation
GET
- source?ids={list-of-ids}
- trans/{localeId}?ids={list-of-ids}
- source+trans/{localeId}?ids={list-of-ids}

PUT 
- /trans/{localeId}
Same observation here. 
Why even add the `addTransUnit` method if all it is doing is being a proxy for put.
Make it implement the `Map` interface if you want to, but use `<String, TransUnit>` for the generics.